The present invention relates to a sound emitting and collecting apparatus, a sound source separating unit and a computer-readable medium having a sound source separation program, and can be applied to a communication terminal, an audio device and the like that are required to separate only sound (hereinafter referred to as a target sound) that comes from a sound source in a predetermined direction, from voice and sound etc. captured by a microphone, for example.
For example, when voice communication is input into a smart phone or when a voice command is input into an audio device, a smart phone or the like, it is desirable that the device that receives voice extracts only voice coming from the front where the mouth of a user is assumed to be, by distinguishing it from voice, music and noise etc. that come from other directions.
Japanese Patent Application Publication No. JP-A-2013-061421 discloses a system (a sound source separation system) which captures sounds input to two microphones and suppresses surrounding noise based on a phase difference between the input sounds (electrical signals), thus extracting a target sound that comes from a predetermined direction (the front, for example) of the microphones.
A target sound extraction method described as a third embodiment in Japanese Patent Application Publication No. JP-A-2013-061421 is a technique that suppresses noise components (non-target sounds) that come from the left and right, by multiplying an input sound signal by a suppression coefficient for each frequency component. The suppression coefficient corresponds to a correlation between two signals obtained by forming two directivities having dead angles to the left and right of the microphones. A target sound extraction method described as a fourth embodiment in Japanese Patent Application Publication No. JP-A-2013-061421 is a technique that forms a directivity having a dead angle to the front of the microphones, and suppresses noise components (non-target sounds) that come from the left and right by subtracting, from the input sound signal, a signal obtained by forming the directivity, as noise components that come from the left and right.